Thursday, October 12, 2006

Science of the Mind

I'm always on the lookout for cool stuff to use in intro psych classes, my primates class, or in a new line of research. Here's a random selection of stuff I've found lately.Be sure to read the five star story!

**The BBC is airing a new show "Chimps Are People Too," a documentary with Sue Savage-Rumbaugh and Kanzi, the bonobo famous for his language and Pac-Man playing skills. As far as I can tell, having not yet seen the show, it's about pointing out the similarities between humans and non-human apes that reveal qualities of "personhood." Granting them special status as "people" would of course entail a major change in how laboratory research is done, not to mention keeping them on display in zoos. This is the goal of the Great Ape Project.

*****My dissertation committee cheerleader has been getting a lot of press for her newly published article on cryptic ovulation. The popular press headline floating around reads: "Fertile women dress to impress, U.S. study finds." It's classic evolutionary psychology stuff. Ethologist Karl Grammer discovered about ten years ago that women who are ovulating show more flesh at singles bars. Haselton found the same thing happened for college students who were asked to show up at her lab two different times to participate in a research project. When the women arrived during the time they were ovulating and most likely to become pregnant if they had sexual intercourse, they wore more revealing clothing, flashier jewelry, and more trendy clothes.

This fits with the idea that although humans don't overtly advertise when they are ovulating (as some primates - chimps, bonobos, baboons - do with giant pink ano-genital skin swellings), they still send cryptic signals that they are fertile. The science reporting in the press releases and interviews is rather dismal. "Another non-winner for science writing skill" says my scientifically astute journalist husband. He's also heard me lecture on this subject before! I'd like to see these articles get into why this is significant and worth talking about on a theoretical level.

See, knowing that a species overtly advertises ovulation tells us about that species' ancestral social organization.

Fewer than 10% of female primates overtly advertise when they are most likely to conceive. This information is very valuable for males because they can use it to avoid wasting time and energy courting a female who is not likely to become pregnant. What's really interesting is that solitary primates (like orangutans) do not have the visible swellings that are so pronounced for chimps and baboons. Monogamous species don't overtly advertise fertility either. You would think that being solitary would raise the stakes for males. Ditto for monogamous males. If they know when their mate is most fertile, they can guard her when she is and prevent other males from inseminating her. Monogamous and solitary species should overtly advertise, but they don't.

When we survey the primate species that have overt advertisements of ovulation, we see they tend to live in multi-male, multi-female social groups in which females mate with multiple males more or less indiscriminately. A female chimp typical mates with nearly every adult male in her group when she sports the equivalent of the human female's short skirt, plunging neckline top and flashy jewelry. In other words, the general rule of thumb is that cryptic ovulation (the subtle changes in appearance that Haselton found) are associated with species that have relatively monogamous females. Species in which females flaunt their fertility tend to be composed of Nelly Furtado-style promiscuous girls.

Thus, based on this evidence for cryptic ovulation among humans, we can infer that our ancestors may have evolved in groups that tended to be composed of one male with a female or group of females who tended to be relatively monogamous with him. Other lines of evidence from comparative anatomy (testicle size and penis length) suggests instead that our ancestors probably lived in groups with a significant amount of male-male competition over females and female promiscuity to drive males to evolve relatively large testicles (more sperm) who could then win paternity at the level of sperm competition.

My own guess, and that is all it is, albeit a professinal one (!) is that human ancestors tended to be monogamous but did cheat opportunistically and regularly. Having totally concealed ovulation means that a male never knows when to guard the female, so he has to be present all of the time, thus we get pairbonding. If ovulation is slightly noticeable, a woman might use her subtle signals to achieve an extra-pair courtship, a secret lover if you will.

Is that so hard to work into a story?

***Male and female voices are processed differently by the brain which suggests that perhaps male and female brains have different ways of working out dominance differences based on voice. One reader commented, "It looks like the team stumbled on a key to the mechanism that works out dominance in the male status hierarchy." This is related to a study I reported on back in August about female preference for deeper, more dominant/masculine male voices. It's a great post, definitely worth a read if you want to learn more about evolutionary psychology! In a nutshell, that study provided evidence that male voices have been sexually selected to be deeper. The study I just found provides evidence that these differences might show up at the level if neuroanatomy, an important link between evolutionary theory and actual behavior. Another study "Men Act Like Dogs to Show Dominance" identified that men unconsciously lower their voices when talking to someone they think is less dominant. In essence, whoever has the lower pitched voice signals dominance.

My undergraduate thesis explored dominance displays through eye contact. I should blog about that some time... I think it's better than my MA thesis. Hell, it might be better designed than my dissertation. All of my college friends (who are probably the only ones still reading this lengthy post) remember well my knack for writing dissertations in college. We all thought it was just a joke, but it turns out there was a healthy portion of truth to it.

Anyhow, I have been toying with the idea of launching a new research project once I finish my dissertation. I'd like to explore human female vocal dominance. The authors of these studies imply that it's not worth it to study modulation of female pitch in social contexts because women have not been sexually selected to have higher pitched voices. That may be, but I think these *guys* who published those studies might buy into the old theory that women don't have dominance hierarchies and that status differentials are irrelevant to women. Well, I am here to say that is bull. It may only be my personal experience, but I am intensely aware of female dominance plays. I really want to do the study I have planned out in my head. I should sit down and write it all down. It's so simple. I just need a way to measure pitch changes during a conversation ...

Coming soon: Island of the Colorblind by neurologist Oliver Sacks. This is easily one of the coolest videos I have seen for use in intro psych! I was totally captivated by it. I base some of my story of cones and color vision and acuity and sensitivity to light on a character from the movie K-Pax, a science fiction story in which Kevin Spacey plays an alien from a low-light planet who has a hard time on earth because the bright light hurts his eyes. The first time I taught intro psych FIVE years ago (!) the movie had just come out. Now, no one recognizes it so I need a new hook. In walks Oliver Sacks and his story of an equatorial island populated by people who are completely colorblind. They are the real life version of the K-Pax character who I thought was completely fictional. The students really enjoyed this video - it had frequent drug references. I highly recommend it. And, I see used copies of the Sacks book are available for less than 2 dollars from Amazon.

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About Me

I'm a papermaker, a newspaper editor, and have a PhD in primate social psychology — I guess you could say I am a paper expert! Toddler Field Notes and her two canine companions — both Newfoundlands — make frequent appearances here.